Exam 3 - information Flashcards
What is Paleoanthroplogy?
the interdisciplinary study of the hominin fossil record
What is a fossil?
Preserved remains, or traces of animals, plants, or other organisms that turned into rock
What is the process of fossilization?
process where the organic components of a material are replaced with minerals
What is relative dating?
Determining if a object is younger or older in relation to something else
TECHNIQUES:
-principle of superimposition
-Biostratigraphy
What is the Principle of Superimposition?
Rocks are deposited in layers, thus the oldest is on the bottom, and the youngest is on top
What is Biostratigraphy?
Relative dating technique that uses the association of fossils in strata (distinguishable layers in rock) to determine each layers to determines layers approx. age
What is Chronometric Dating?
Determining the absolute age of an object
What is Radiometric Dating?
- Measures ratio of carbon-13 to carbon-12
- has a half life of 5730 years
- Organic material is 1,000-75,000 years old
What is Potassium-Argon Dating?
- Measures ratio of potassium-40 to argon-40
- half life of 1.25 billion years
- Volcanic rocks 1-5 million years old
What is Paleomagnetic Dating?
- Dating method based on earths shifting magnetic poles
- used on sedimentary rocks up to 5 million years old
What is the importance of the skeleton?
It gives us clues for:
- locomotion
- soft tissue details (brain size, muscles)
- diet
- individual features (sex, age, pathology)
What are key hominin features?
- bipedal locomotion
- large brain size
- tool making
- dentition
What is mosaic evolution?
- Pattern of evolution where the ratio of evolution of one functional system varies from that of other systems
- Different functional systems arose at different times
What is the Savannah Hypothesis?
Traditional bipedalism theory where the forests turned into savanahs, forcing adaptation to move about the ground. No real evidence
What is the Visual Surveillance Hypothesis?
- Standing upright gave us vision improvement of surroundings (spot predators, locate food, find others)
- Still clumsy runners
What is the Thermoregulation Hypothesis?
- Vertical body position helped early hominins stay cool
- However many primates solve this by resting during the hottest points of the day
What is the Carrying Stuff Hypothesis?
-bipedalism theory where we walked upright to carry things such as food, young, and weapons
What is the Bush Hypothesis?
- bipedalism theory where we started changing out diets to fruit
- Can reach fruit and revert to quadrepedalism
What is the Aquatic Ape Theory?
- bipedalism theory where our ancestors would wade through shallow water to forage for food
- buoyant water helped them develop upright walking
- however no primates forage in water and there are tons of predators
What is the Energy Efficient Theory?
- Bipedalism = more efficient for long distances
- early on it was inefficient
What was Lovejoy’s Provisioning Hypothesis?
Males carry resources back to females and dependent young
- increased offspring survival
- increased female reproduction rates
- but assumes monogomy and fossils show sexual dimorphism
What was Postural Feeding?
-Bipedalism needed for support on smaller branches
What are the key advantages of Bipedalism?
- Energy efficient
- allows use of hands for carrying
- better view of surroundings
- helps keep body cool
What is a bipedalism feature of skulls?
forearm magnem: located at base of skull
What is a bipedalism feature of the spine?
S-shaped curvature
What is a bipedalism feature of the pelvis?
Glutius maximus: repositioned behind the hip
What is a bipedalism feature of the femur?
Angled inward
What is a bipedalism feature of the knee?
robust joint, allows for full extension and locking
What is a bipedalism feature of the foot?
Enlarged and in-line big toe, traverse and longitudinal arches
What are the stages of Bipedalism?
Early Bipedalism: 7-6 myo, occasionally used biped
Occasional to Habitual Bipedalism: environmental change to terrestrial resources, natural selection favored bipeds
Obligate Bipedalism: environmental shift to savannahs, biped was more efficient for distance running
What are running adaptations caused from Bipedalism?
Nuchal ligament (head stabilization) Longer legs (longer strides) Expanded joint surfaces (shock absorbers) Increased balance Increased vision, image stabilization More power, spring energy, shocks
What were the Pre-Australopithes?
Possible first ancestor in human lineage
What was the evidence of Bipedalism in Sahelothropus tchodensis?
based on the orientation of the faramen magnum (spine)
What was the evidence of Bipedalism in Orrorin Tugenensis?
- Proximal femur
- Slightly anteriorly rotated spherical head
- Presence of an intertrchant groove
- Elongated neck
What was the evidence of Bipedalism in Ardipithecus Ramidus?
- No prognation below nasal aperture
- non honing complex
- humerus
What is prognathism?
- Forward projection of the face
- Generally the maxilla or mandible
What is the Honing Complex?
Upper canine is sharpened
-Diastema: gap to accommodate canines
What are the key features of Australopithes?
- bipedal
- small brains
- large teeth
- thick enamel
What are key features of the Genus Paranthropus?
adaptations for powerful chewing
- huge molars and promolars
- large deep mandibles
- flatter face
- broad flaring cheekbones
- saggital chest
What are key trends of the genus Homo?
- increased cranial capacity
- brain complexity
- reduced tooth size
- improved bipedalism
- use of tools
What is the difference between Homo habilus and Homo rudolfensis?
sheer size of brain, teeth, and longer face
What tools did H. erectus use?
- Acheulean tools
- bifacial handaxes
- concerned with shaped
What tools did H. Habilus use?
- Oldowan tools
- Crude, pebble tools
- interested in sharp edges
